The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
As pollution is getting more serious, use of non-polluting energy becomes more important. Particularly, air pollution in a big city is getting more serious. One of major causes of air pollution is exhaust gas of vehicles.
In order to solve such problems due to exhaust gas and enhance fuel economy, environmentally-friendly vehicles have been developed and used.
The environmentally-friendly vehicles include hybrid electric vehicles that use a drive motor and an engine as power sources, plug-in hybrid electric vehicles (PHEVs) provided with a high voltage battery of large capacity and charged by external electricity, and etc.
The environmentally-friendly vehicles provide various driving modes such as electric vehicle (EV) mode where torque of the drive motor is used for running, hybrid electric vehicle (HEV) mode where both of the engine torque and the motor torque are used for running, charge mode where the engine is operated to charge a battery, and etc.
The drive motor includes components such as a permanent magnet and a coil for outputting power. The components may be thermally degraded in non-reversible manner at a high temperature condition higher than a certain temperature.
Therefore, if a motor temperature of the environmentally-friendly vehicle is higher than or equal to a reference temperature, overheating of the motor is prevented by reducing a motor output or stopping the motor and the environmentally-friendly vehicle runs using the engine. According to conventional arts, a region where the vehicle runs at EV mode may be reduced due to protection logic against overheating the motor, and marketability of the environmentally-friendly vehicle may be deteriorated due to frequent drive of the engine.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.